Long Duration Winter Storm
Moderate to Heavy Snow - Mixed Precipitation
Evening Convective Snow Squall Event
March 18-19, 2013

A long duration significant winter storm unfolded across the Northeast from the early evening on Monday March 18, continuing through 11:59pm on Tuesday March 19. Snow came in several phases with the system along with a period of mixing where sleet and freezing rain/drizzle developed across mainly the Catskills, mid Hudson valley, Berkshire and Litchfield counties roughly from 3am through 10am on the 19th after an initial installment of snow. Snow accumulations for the event generally ranged from 8"-12" across the Mohawk valley, Adirondacks, Lake George/Saratoga Regions and across the higher elevations of southern Vermont. 5"-8" amounts were common throughout the western Catskills, Schoharie County, the Capital Region, Vermont, and northern Berkshire County, with a range of 2"-5" common in the mid Hudson valley, central and southern Berkshire and Litchfield counties where mixing occurred and the system's dry slot had the largest impact.

Round 1:
The first round of snow was generated as low pressure at the surface over the Ohio valley approached the region and high pressure over eastern New England moved away. The combined circulations around these system produced a strong southeast inflow of warm moist air in the mid levels of the atmosphere flowing in off the Atlantic ocean, which when it encountered the cold surface air over the Northeast was forced to rise sharply. This rising motion, or overrunning as it is termed in meteorology, generated a band of moderate to heavy snow which moved across the region from the early evening hours on the 18th through 2-3am on the 19th. Brief bursts of heavy snow with 1" per hour snowfall rates occurred within this zone leaving a 1"-4" of snow accumulation by midnight and a general range of 2"-7" by 8am Tuesday. Snowfall was enhanced in a zone which included much of Fulton, southern Hamilton, central and northern Saratoga and Warren counties as the southeast flow was forced to ascend more strongly due to the rise in the terrain across this region. It was in this zone where accumulations by 8am ranged from 5"-7" on average. As the main zone of overrunning moved north of the area, after 3am, snow became fairly light and intermittent mixing with sleet, freezing rain, and freezing drizzle, across especially the Catskills, mid Hudson valley, Berkshire and Litchfield counties as an above freezing nose of air pushed in from off the Atlantic for a time into the morning.

Round 2:
A second round of snow blossomed across the entire region from the mid morning through the early afternoon as the upper level portion of the storm swung an arm of energy across eastern New York and western New England. The upper level forcing produced a new zone of strong lift which caused a band of moderate to heavy snow to set-up producing an additional 2"-5" of snow on average across mainly the Mohawk valley, Capital Region to northern Berkshire County on north with an inch or two across the Catskills, mid Hudson valley, and Berkshire counties where enough mid level warm air lingered to support a mixture of snow, sleet, and freezing rain. Snowfall rates of up to 2" per hour occurred in the Capital Region and points north for brief period from the late morning into the early afternoon before this zone of snow shifted east and out of the region. Areas of light to locally moderate snow flared up in the wake of this main snow zone through the mid to late afternoon in and around the Capital Region, Mohawk valley, Lake George-Saratoga regions, and the Adirondacks and Vermont. A brief enhancement occurred in and around the Capital Region during the mid afternoon due to Mohawk-Hudson convergence (MHC) as a period of westerly wind coming down the Mohawk valley converged with a northerly wind coming down the Hudson valley caused lift and thus an enhanced burst of snow for about an hour.

Round 3: Intense Snow Squall Event: 5pm to 11pm:
The final round of accumulating snow with the event occurred as steep low level lapse rates developed during the evening with the approach and passage of a strong short wave disturbance across the region causing a line of blinding snow squalls to move through during the evening. The following were the 00z upper air observations at Albany: 21 dm height falls at 500 mb; 500 mb temperature of -34° C; 700 mb temperature of -17° C; 800 mb temperature of -6° C; dewpoint depression of 1; left front quadrant of a 145 knot jet max at 300 mb; and a surface temperature near 32°. These observations indicated an unstable environment favorable for convective development along the region of greatest height falls aloft. Snow squalls produced wind gusts up to 35 mph, a few flashes of lightning and thunder between 7pm and 9pm in the Schoharie and Mohawk valleys, and brief whiteout conditions with up to an additional 2" of snow accumulation. The squalls entered the western Catskills and western Mohawk valley shortly after 5pm, moved down the Mohawk valley and into Schoharie County through 7:30pm, then into and through the Capital Region through 9:00pm, and finally dissipating in Vermont and Berkshire County close to midnight. The passage of the snow squall line essentially marked the end of the event with only widely scattered flurries and snow showers lingering into the pre-dawn hours on Wednesday March 20.

WeatherNet 6 Snowfall Accumulation Distribution Map
March 18-19, 2013

WeatherNet 6 Snowfall Distribution March 18-19, 2013 

WeatherNet 6 Snowfall Reports - Time of Report Marked (March 19)
Note: Any report prior to 6pm does not include any additional snow from the evening round of snow squalls that may have fallen
March 18-19, 2013

Town County Snowfall Report Town County Snowfall Report
Lanesborough, MA Berkshire 5" (6am/20th) Pittsfield, MA Berkshire 4" (7am/20th)
Alford, MA Berkshire 2.5" (8am/20th) Savoy, MA Berkshire 13.5" (Noon/29th)
Clarksburg, MA Berkshire 7.5" (5am/20th(      
Colonie Albany 8.2" (9:30pm) Potter Hollow Albany 8" (10:30pm)
Cohoes Albany 6.5" (6pm) Newtonville Albany 8.7" (11pm)
S. Berne Albany 6.5" (6pm) Guilderland Albany 5.3" (6:30pm)
Knox Albany 9.4" (9pm) Glenmont Albany 6.5" (5am/20th)
Voorheesville Albany 7" (10:30pm) Green Island Albany 7" (6pm)
Ravena Albany
3" (7pm)
Medusa Albany 7" (6:30pm)
Kinderhook Columbia 3.6" (11pm) Hudson Columbia 3.5" (6pm)
Austerlitz Columbia 4.2" (11pm) Ghent Columbia 2" (11pm)
Livingston Columbia 2.3" (11pm) Chatham Center Columbia 4" (5am/20th)
Taghkanic Columbia 3.4" (6am/20th) North Chatham Columbia 5.1" (4:30pm)
Arkville Delaware 7" (10:30pm)      
Caroga Lake Fulton 13" (7am/20th) Johnstown Fulton 8" (5pm)
Fish House Fulton 12" (5pm) Perth Fulton 9" (5pm)
Broadalbin Fulton 9" (Noon) Ephratah Fulton 9.5" (8am/20th)
Catskill Greene 3" (11:30pm) Round Top Greene 4" (10pm)
Halcott Greene 4" (8pm) Greenville Greene 7.8" (7pm)
Prattsville Greene 4.5" (5pm) Ashland Greene 4.5" (Noon)
Wells Hamilton 10" (8pm) Hoffmeister Hamilton 10" (5:30pm)
Indian Lake Hamilton 12.5" (6am/20th) Piseco Hamilton 11.5" (6am/20th)
Amsterdam Montgomery 10.5" (11pm) Glen Montgomery 12" (10:30pm)
Fonda Montgomery 11.1" (10:30pm) Hessville Montgomery 7.5" (9pm)
Palatine Bridge Montgomery 4" (5pm) Stone Ridge Montgomery 8.1" (5pm)
Florida Montgomery 9" (5pm)      
Oneonta Otsego 5" (10:30pm) Worcester Otsego 8.8" (6am/20th)
Cherry Valley Otsego 5.5" (5:30pm) Schenevus Otsego 8.8" (3pm)
Center Brunswick Rensselaer 7.8" (11pm) Schaghticoke Rensselaer 8.7" (10pm)
Berlin Rensselaer 4.5" (7am/20th) Speigletown Rensselaer 7" (4:30pm)
Grafton Rensselaer 9" (6am/20th)      
Malta Saratoga 12" (10:30pm) Charlton Saratoga 12.5" (10pm)
Saratoga Springs Saratoga 12.9" (9:30pm) Milton Saratoga 13" (9pm)
Ballston Lake Saratoga 9" (5pm) Hadley Saratoga 12" (7:30pm)
Porter Corners Saratoga 15" (7pm) Corinth Saratoga 9.8" (6pm)
Wilton Saratoga 11.5" (4pm) Clifton Park (Oaks) Saratoga

8.5" (11pm)

Jefferson Schoharie 6" (11pm) Richmondville Schoharie 6" (9pm)
Sharon Springs Schoharie 6" (6pm) Fulton Schoharie 7.5" (5pm)
Huntersland Schoharie 7" (6am/20th) Middleburgh Schoharie 7.6" (4:30pm)
Duanesburg Schenectady 7" (10:30pm) Scotia Schenectady 7" (6pm)
Kingston Ulster 4.8" (11pm) Ulster Park Ulster 5.5"
Phoenicia Ulster 5.7" (5:30pm) New Paltz Ulster 5.3" (5pm)
West Hurley Ulster 3.5" (5pm) Saugerties Ulster 3.6" (4:30pm)
Esopus Ulster 4" (4:30pm) Highmount Ulster 10" (8am/20th)
Lake Luzerne Warren 14" (11pm) Warrensburg Warren 10.5" (9pm)
Queensbury Warren 8.8" (6:30pm) Brant Lake Warren 11" (7am/20th)
Salem Washington 5.5" (5:30pm) Kingsbury Washington 9" (5pm)
Hudson Falls Washington 9.2" (5am/20th)      
Landgrove, VT Bennington 12.3" (8am/20th) W. Arlington, VT Bennington 4.5" (6pm)
Woodford, VT Bennington 17.0" (Noon/20th) Danby, VT Rutland 10.5" (6am/20th)
West Rutland, VT Rutland 6" (5pm)